Hydrogen peroxide administered into the rat spinal cord at the level elevated by contusion spinal cord injury oxidizes proteins, DNA and membrane phospholipids, and induces cell death: Attenuation by a metalloporphyrin. (29th January 2015)

• Record Type: Journal Article
• Authors: Liu, D.; Bao, F.
• Is Part Of: Neuroscience. Volume 285(2015)
• Page Start: 81
• Page End: 96
• Publication Date: 2015-01-29
• Subjects: 2, 3 and 2, 5-DHBA 2, 3- and 2, 5-dihydroxybenzoic acid -- 8-OHdG 8-hydroxy-2-deoxyguanosine -- ACSF artificial cerebrospinal fluid -- ANOVA analysis of variance -- DNP 2, 4-dinitrophenyl -- H2O2 hydrogen peroxide -- [H2O2] hydrogen peroxide concentration -- HNE 4-hydroxy-nonenal -- HPLC high-pressure liquid chromatography -- i.p. intraperitoneally -- MDA malondialdehyde -- MLP membrane lipid peroxidation -- MnTBAP Mn (III) tetrakis (4-benzoic acid) porphyrin -- NO nitric oxide -- NSE neuron-specific enolase -- O2− superoxide anion -- OH hydroxyl radical -- ONOO− peroxynitrite -- PBS phosphate-buffered saline -- RNS reactive nitrogen species -- ROS reactive oxygen species -- SCI spinal cord injury -- TEM transmission electron microscopy -- TUNEL terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate-(dUTP)-biotin nick end labeling; hydrogen peroxide -- spinal cord injury -- Mn (III) tetrakis (4-benzoic acid) porphyrin -- proteins and DNA oxidation -- membrane lipid peroxidation -- apoptotic cell death; Neurochemistry -- Periodicals; Neurophysiology -- Periodicals; Neurology -- Periodicals; Neurochimie -- Périodiques; Neurophysiologie -- Périodiques; Neurochemistry; Neurophysiology; Electronic journals; Periodicals; Electronic journals; 612.8
• DOI: 10.1016/j.neuroscience.2014.10.063
• Languages: English
• ISSNs: 0306-4522

Abstract

Highlights: Established spinal cord injury (SCI)-elevated extracellular H2 O2 level. SCI-elevated H2 O2 induces oxidation and cell death in normal rat spinal cord. SCI-elevated H2 O2 induces apoptosis in normal rat spinal cord. Caspase activation is a mechanism of SCI-elevated H2 O2 -induced apoptosis. MnTBAP attenuates oxidation and cell death by scavenging excess H2 O2 . Abstract: We previously demonstrated that hydrogen peroxide concentration ([H2 O2 ]) significantly increases after spinal cord injury (SCI). The present study explored (1) whether SCI-elevated [H2 O2 ] is sufficient to induce oxidation and cell death, (2) if apoptosis is a pathway of H2 O2 -induced cell death, and (3) whether H2 O2 -induced oxidation and cell death could be reversed by treatment with the catalytic antioxidant Mn (III) tetrakis (4-benzoic acid) porphyrin (MnTBAP). H2 O2 was perfused through a microcannula into the uninjured rat spinal cord to mimic the conditions induced by SCI. Protein and DNA oxidation, membrane phospholipids peroxidation (MLP), cell death and apoptosis were characterized by histochemical and immunohistochemical staining with antibodies against markers of oxidation and apoptosis. Stained cells were quantified in sections of H2 O2 -, or artificial cerebrospinal fluid (ACSF)-exposed with vehicle-, or MnTBAP-treated groups. Compared with ACSF-exposed animals, SCI-elevated [H2 O2 ] significantly increased intracellular protein and DNA oxidation by threefold and MLP by eightfold in neurons, respectively. H2 O2 -elevated extracellular malondialdehyde was measured by microdialysis sampling. We demonstrated that SCI-elevated [H2 O2 ] significantly increased extracellular malondialdehyde above pre-injury levels. H2 O2 also significantly increased cell loss and the numbers of terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate-(dUTP)-biotin nick end labeling (TUNEL)-positive and active caspase-3-positive neurons by 2.3-, 2.8-, and 5.6-fold compared to ACSF controls, respectively. Our results directly and unequivocally demonstrate that SCI-elevated [H2 O2 ] contributes to post-SCI MLP, protein, and DNA oxidation to induce cell death. Therefore, we conclude that (1) the role of H2 O2 in secondary SCI is pro-oxidation and pro-cell death, (2) apoptosis is a pathway for SCI-elevated [H2 O2 ] to induce cell death, (3) caspase activation is a mechanism of H2 O2 -induced apoptosis after SCI, and (4) MnTBAP treatment significantly decreased H2 O2 -induced oxidation, cell loss, and apoptosis to the levels of ACSF controls, further supporting MnTBAP's ability to scavenge H2 O2 by in vivo evidence.